<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id="demo3">
        <span v-html="link"></span>
    </div>

<script src="https://unpkg.com/vue@2.6.1/dist/vue.min.js"></script>
<script>
    var deme3 = new Vue({
        el: '#demo3',
        data: {
            link: '<a href="#">this is a link</a>'
        }
    });
</script>
</body>
</html>